Valve Lift

The "lifting" part of a camshaft is centered on the lobes' base circle. This is the minimum radius that is described. Cam lift is the increase above this base circle to the maximum deflection above it. Rocker arm motors have (usually) different lengths on either side of their pivots. This ratio is almost always greater than unity. Where the valve tip is closer to the cam than its pivot it is less. On XV motors this ratio is 1:1.347. That is to say that the cam lift times the rocker ratio is the valve lift - the distance the vlalve face lifts off the valve seat. Say a mound of material above the cam's base circle lifts the rocker pad by .400". At the the pivot, this is multiplied by the rocker ratio. And we get (.400")X1.347 equals .5388."

Valve Lift
Duration
Timing

More to come . . .

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